BEHAVIOUR
•  Def’n - Externally observable
muscular activity triggered by some
stimulus
OR
•  What an animal does while
interacting with its
environment
A BROAD BEHAVIORAL
PERSPECTIVE
•  When studying behavior one should
consider both the ecological and
physiological context upon which the
stimulus is received
TINBERGEN’S 4 QUESTIONS
•  Functional (why)
•  Causal (how)
•  Ontogeny (development)
•  Phylogeny (lineage)
ANOTHER POINT
•  Behavioural traits
should be treated like
any other trait except
that most behavioural
traits are labile (highly
changeable)
DECISION
•  Def’n - ability to respond differently to
different situations
TWO MORALS
•  We use rules too
•  Human chauvinism can be detrimental to
studies of behavior
A FACT
•  Most organisms use simple rules to solve
problems e.g. If X do Y
A PROBLEM
•  Reliable information is in short supply
A FACT
•  Behaviour often has tradeoffs
FEEDING MORTALITY
TRADEOFF IN MOSQUITOES
•  Protein acquisition can be costly
tradeoffs
DO UNFEDS ESCAPE MORE
OFTEN?
1
0.8
FED UNFED
0.6
p < 0.0001
0.4
0.2
0
Pre Pounce
Escape
Pounce
Category
2 DIFFERENT PROCESSES
•  Anti-predator behaviour •  Mate acquisition behaviour FRUIT FLY BIOLOGY
•  4 STAGES
– Egg, larva, pupa, adult
3 IMPORTANT FACTS
ABOUT FRUIT FLIES
•  Mothers choose hosts for their offspring
•  Each host can support a single larva
•  Adults are egg limited
FLIES MIMIC DANGEROUS
PREY
EMPIRICAL EVIDENCE
•  Ovipositing flies are susceptible to
predatory wasps whereas vigilant flies are
much less susceptible
A FACT
•  Time invested in vigilance is traded off
against time spent in food and host search
TO US:
•  Tide pool sculpins look like their
background
IMPORTANT FACT
•  Rocks don’t move - they don’t eat either
THE DECISION TO CHASE
PREY SHOULD DEPEND UPON
•  Threat from predation
•  Payoff from moving (chasing)
A PROBLEM
•  Estimating risk from predator
is difficult
YOU WEREN’T ATTACKED
BECAUSE:
•  Predator wasn’t present (Is it now?)
•  Predator didn’t see you
•  Predator chose not attack
NOT JUST SCULPINS
•  Grasshopper camouflage success depends
upon background and movement
AN OBSERVATION
•  Gazelles sometimes stot
BEST EXPLANATION FOR
STOTTING
•  Gazelle is “telling” the predator that it
has been seen
A FACT
•  A “prepared” gazelle is harder to capture
than an unprepared individual
NOT JUST ON LAND
•  Goby fish also bob or stot when exposed to
alarm pheromones
CONCLUSION
•  Flies are dishonest
•  Sculpins are dishonest
•  Gazelles are honest